A wheel loader representing a mobile work vehicle includes a traveling apparatus for running a vehicle and a work implement for various works such as excavation. The traveling apparatus and the work implement are driven by drive force from an engine.
In general, a wheel loader often simultaneously performs such works as traveling and loading. For example, in an excavation work, a work implement is pushed into a heap of soil by moving the vehicle forward and the work implement is raised.
The soil is thus scooped in the work implement. Therefore, it is important to allocate power of the engine to the traveling apparatus and the work implement in a balanced manner.
In order to operate the vehicle in a good balance, however, skills are required.
For example, when an unskilled operator excessively presses an accelerator during excavation and excessively pushes the work implement into soil, the vehicle cannot move forward and is stopped. Since drive force for running the vehicle is excessively large in this state, drive force for raising the work implement is lowered. Therefore, even though a work implement operation member is operated to a maximum extent, the work implement cannot be raised. In such a state, in order to protect a hydraulic pump, a hydraulic circuit for supplying a hydraulic oil from the hydraulic pump to the work implement enters a relief state. In such a stall state that the vehicle stalls, a state that engine power is high continues and fuel efficiency becomes poor (an amount of consumption of fuel increases).
An automatically operated wheel loader of which vehicular body automatically travels toward an excavation object such as soil and stones without requiring an operator, of which bucket runs into the excavation object with the traveling operation, and of which bucket and arm are thereafter activated to perform an excavation operation has also been proposed (PTDs 1 and 2).